AD7674ACPZRL Analog Devices Inc, AD7674ACPZRL Datasheet - Page 21

• Manufacturer Part Number: AD7674ACPZRL
• Description: 18-Bit,800kSPSSARADC
• Manufacturer: Analog Devices Inc
• Series: PulSAR®r

Specifications of AD7674ACPZRL

• Number Of Bits: 18
• Sampling Rate (per Second): 800k
• Data Interface: Serial, Parallel
• Number Of Converters: 1
• Power Dissipation (max): 138mW
• Voltage Supply Source: Analog and Digital
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 48-VFQFN, CSP Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: EVAL-AD7674CBZ - BOARD EVALUATION FOR AD7674
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PARALLEL INTERFACE
The AD7674 is configured to use the parallel interface with an
18-bit, a 16-bit, or an 8-bit bus width, according to Table 7. The
data can be read either after each conversion, which is during
the next acquisition phase, or during the following conversion,
as shown in Figure 37 and Figure 38, respectively. When the
data is read during the conversion, however, it is recommended
that it is read only during the first half of the conversion phase.
This avoids any potential feedthrough between voltage
transients on the digital interface and the most critical analog
conversion circuitry. Refer to Table 7 for a detailed description
of the different options available.
CS = RD = 0
BUSY
DATA
RESET
CNVST
Figure 36. Master Parallel Data Timing for Reading (Continuous Read)
Figure 37. Slave Parallel Data Timing for Reading (Read after Convert)
BUS
BUSY
DATA
RD
CS
BUS
CNVST
BUSY
DATA
BUS
t
12
t
3
PREVIOUS CONVERSION DATA
Figure 35. RESET Timing
CONVERSION
CURRENT
t
t
1
9
t
13
t
10
t
t
8
4
t
11
NEW DATA
03083-0-035
03083-0-037
03083-0-036
Rev. A | Page 21 of 28
SERIAL INTERFACE
The AD7674 is configured to use the serial interface when
MODE0 and MODE1 are held high. The AD7674 outputs 18
bits of data, MSB first, on the SDOUT pin. This data is
synchronized with the 18 clock pulses provided on the SCLK
pin. The output data is valid on both the rising and falling edge
of the data clock.
MASTER SERIAL INTERFACE
Internal Clock
The AD7674 is configured to generate and provide the serial
data clock SCLK when the EXT/ INT pin is held low. The
AD7674 also generates a SYNC signal to indicate to the host
when the serial data is valid. The serial clock SCLK and the
SYNC signal can be inverted if desired. Depending on the
RDC/SDIN input, the data can be read after each conversion or
during the following conversion. Figure 40 and Figure 41 show
the detailed timing diagrams of these two modes.
Usually, because the AD7674 is used with a fast throughput, the
Master Read during Conversion mode is the most
recommended serial mode.
In Read during Conversion mode, the serial clock and data
toggle at appropriate instants, minimizing potential
feedthrough between digital activity and critical conversion
decisions.
PINS D[15:8]
PINS D[7:0]
Figure 38. Slave Parallel Data Timing for Reading (Read during Convert)
CNVST,
CS = 0
BUSY
DATA
BUS
A0, A1
RD
CS
RD
HI-Z
HI-Z
Figure 39. 8-Bit and 16-Bit Parallel Interface
t
12
t
3
CONVERSION
t
PREVIOUS
12
t
HIGH BYTE
LOW BYTE
1
t
13
t
4
t
12
HIGH BYTE
LOW BYTE
AD7674
03083-0-039
03083-0-038
HI-Z
HI-Z
t
13